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目的对2012年陕西省连续发生的两起B型流感暴发疫情进行实验室诊断,分析暴发疫情分离株的HA基因、NA基因的基因特征和变异特点。方法对两起暴发疫情流感样病例标本进行real-time PCR核酸检测,用MDCK细胞培养流感病毒,提取病毒核酸,用RT-PCR扩增病毒HA基因和NA基因,测定核苷酸序列,用DNAman、Mega软件分析结果。结果两起流感暴发疫情均由B型流感病毒Victoria系引起。其HA基因与2010年-2011年北半球疫苗株相比,无核苷酸的丢失、插入、糖基化位点的改变,氨基酸的同源性分别为99.15%、98.97%。其NA基因与2010年-2011年北半球疫苗株相比,无核苷酸的丢失、插入、糖基化位点的改变,氨基酸的同源性均为96.35%。两起暴发疫情之间的HA氨基酸序列、NA氨基酸序列的同源性分别为99.83%、99.79%。结论引起两起暴发疫情的流感病毒为同一流行株,未发现耐药株,对神经氨酸酶抑制剂依然敏感。
Objective To diagnose two consecutive outbreaks of influenza B in Shaanxi Province in 2012 and analyze the gene and mutation characteristics of HA and NA genes in outbreaks of outbreaks. Methods Real-time PCR was used to detect influenza-like samples in two outbreaks of influenza outbreaks. The influenza viruses were cultured in MDCK cells and the viral nucleic acids were extracted. The viral HA and NA genes were amplified by RT-PCR. The nucleotide sequence was determined by DNAman , Mega software analysis results. Results Two outbreaks of influenza were caused by the influenza B virus strain Victoria. Compared with the northern hemisphere vaccine strain from 2010 to 2011, the HA gene has no nucleotide loss, insertion, change of glycosylation sites and amino acid homology of 99.15% and 98.97% respectively. Compared with the northern hemisphere vaccine strain from 2010 to 2011, the NA gene has no nucleotide loss, insertion, change of glycosylation site and amino acid homology of 96.35%. The homology of the HA amino acid sequence and NA amino acid sequence between the two outbreaks were 99.83% and 99.79% respectively. Conclusion The two outbreaks of influenza virus caused the same epidemic strain. No drug-resistant strains were found, and neuraminidase inhibitors were still sensitive.